My usual method of copying/dragging the files from a zip file gave a an error on the PDF and failed to extract. This is on a Win7 Pro OS for what it’s worth. I was able to extract the files using 7-Zip and that also indicated an issue as well. The extracted PDF with 7-Zip does seem to open OK.
I haven’t tried to load the actual ‘drm’ file yet, but suspect it’s OK as no apparent errors on extraction occurred.